The present invention relates to polyketone polymers useful as the stationary phase in chromatographic processes for the adsorption of metal ions. It particularly relates to polyketone polymers which are linear alternating polyketone polymers. It has been discovered that certain linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon (polyketone), having appropriate surface area can be used to remove metal ions chromatographically from solution. A significant savings can be obtained in certain processes by scavenging scarce elements from solution, particularly for platinum group metals (PGM's), cobalt, chromium, manganese, antimony and others.
The class of polymers of carbon monoxide and olefins has been known for some time. Brubaker, U.S. Pat. No. 2,495,286, produced such polymers of relatively low carbon monoxide content in the presence of free radical initiators, e.g., peroxy compounds. U.K. No. 1,081,304 produced similar polymers of higher carbon monoxide content in the presence of alkylphosphine complexes of palladium salts as catalysts. Nozaki extended the process to produce linear alternating polymers by the use of arylphosphine complexes of palladium moieties and certain inert solvents. See for example, U.S. Pat. No. 3,964,412.
More recently, the class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon, e.g., polymers of carbon monoxide and ethylene or carbon monoxide, ethylene and propylene, has become of greater interest in part because of the greater availability of the polymers. The polymers, often referred to as polyketones or polyketone polymers, have been shown to be of the repeating formula--CO-(A)--where A is the moiety of unsaturated hydrocarbon polymerized through the ethylenic unsaturation. For example, when the polymer is ethylene the polymer is represented by the repeating formula--CO-(CH.sub.2 -CH.sub.2)--. The general process for the more recent production is illustrated by a number of published European patent application Nos. including 0,121,965 and 0,181,014. The process generally involves the use of a catalyst composition formed from a compound of palladium, cobalt or nickel, the anion of a strong, non-hydrohalogenic acid, and a bidentate ligand of phosphorus, arsenic or antimony.
As used herein, the term "chromatographic processes" is used in a generic sense, referring to processes contacted with a stationary phase, comprising the novel polyketone material of this invention. Accordingly, while as will be described more fully hereinafter, the instant polyketone material possesses a mechanism for the adsorption of metal ions, particularly platinum group metals, within its scope of the invention, utility for other processes, well known to those skilled in the art may exist.